Method and apparatus for manufacturing hollow concrete building blocks



July 28, 1925. 1,547,530

W.'P. STANTON METHOD AND APPARATUS FOR MANUFACTURING HOLLOW CONCRETE BUILDING BLOCKS Filed Sept. 1 1923- 3 Sheets-Sheet l Arrow/5Y3 W. P. STANTON METHOD AND APPARATUS FOR MANUFACTURING HOLLOW CONCRETE BUILDING BLOCKS Filed Sept. 1. 1923 s Sheets-Sheet 2 .WVVENTOR WOLCOTZ P STAN 70M.

A rromwya 1 July .28, 1925. 1,547,530

W. P. STANTON METHOD AND APPARATUS FOR MANUFACTURING HOLLOW CONCRETE BUILDING BLOCKS Filed Sept. 1 1923 3 Sheets-Sheet 5 INWE'NTOR WOLCOTZ P $734NTO/V.

ATTURZVEYS.

Patented July 28, 1925.

UNITED STATES,

PATENT OFFICE.

WOLCOTT I; STANTON, OF BERKELEY, CALIFORNIA, ASSIGNOR T NATIONAL STONE TILE CORPORATION, OF SAN FRANCISCO, CALIFORNIA, A CORPORATION OF CALI- FORNIA.

METHOD AND ArrARAru's non MANUFACTURING HOLLOW CONCRETE BUILDING BLOCKS. 4

Application filed September 1, 1923. Serial No. 660,513.

To all whom it may concern:

Be it known that I, WOLCOTT P. STANTON, a citizen of the United States, residing at Berkeley, county of Alameda, and State of California, have invented new and useful Improvements in Methods and Apparatus for Manufacturing Hollow Concrete Building Blocks, of which the following is a specification.

This invention relates to a method and apparatus for manufacturing hollow concrete building blocks.

The present invention embodies a method and an apparatus for manufacturing concretc building blocks and the like, the object being to produce blocks of great strength and density; to materially increase the output of a plant of a given size; to reduce cost of manufacture; to simplify and improve the casting and stripping operations, and to employ a method which permits the use of a wet mix during the casting operation and stripping or removal of the molds before the concrete begins to set.

One'form which my invention may as 'sume' is exemplified in the following description and illustrated in the accompanying drawings, in which Fig. 1 is a perspective view showing the lay-out and position of the apparatus when in operation.

Fig. 2 is a diagrammatic plan view of th same.

Fig. 3 is a detail cross-section of the trackway showing the position of the sand bed between the tracks, and also showing a mold in position on the rails to receive the concrete.

Fig. 4 is an end view of the sand spreading and levelling device.

Fig. 5 is a perspective View of the float whereby the concrete is spread and smoothed off. 1

Referring to the drawings in detail. and particularly to Fig. 2, it may be stated that the manufacturing plant is laid out as indicated. A. smooth level ground surface is preferred which is approximately 140 feet long and (36 feet wide. Five pairs of tracks are laid on the surface as indicated at 2. 3, 4, 5 and G. and runways such as indicated at 7 are formed between the same. The length of each set of tracks is approximately 100 feet, thus leaving a space at one end for a spur track 8, a concrete mixer 9, a cement shed 10, and material dumps as indicated at 11 and 12, the opposite end indicated at 13 being provided forthe reception and stacking of the concrete blocks when completed. In the operation of a plant of the size here indicated four men are preferably employed, one man to run the mixer, a second man on the molds, a third man to wheel the concrete and to help the man on the molds, and a fourth man who is employed for the purpose of stacking the blocks and keeping up the beds. as will hereinafter be described. Any standard make of concrete mixer will serve in the manufacture of concrete blocks, but the most convenient size for capacity production is a one-sack batch as this permits a more uniform mix by using an even sack of cement in each batch.

Wheelbarrows may be used for transport: ing the concrete from the mixer to themolds, but the best equipment for this purpose, however, is a two-wheeled concrete cart such as indicated at 14, as it is easy to handle,

and a greater output is obtained by its use.

Four sets of molds such as indicated at 15 are usually employed and a single lifting jack of suitable construction as indicated at 16.

The only other equipment required are a pair of stout wooden mallets, a wooden float such as indicated in Fig. 5, a smoothing strip 18,- and finally theremust be some pro vision for preventing waste of concrete over the ends of the mold during the spreading operation, and this isaccomplished by employing a hopper 17 such as shown in Fig. 1. This hopper rests on top of the mold and is advanced from one mold to another as they are being filled. The molds indicated at 15 and the lifting jack 16 are supported by the tracks and are advanced along the casting of the concrete blocks and, secndly, they serve as a support for the concrete blocks during the stripping operation and while the concrete is setting. The sand beds also serve other functions hereinafter to be described. The sand bed being porous serves to admit air to the mold so as to break the suction between the mold and the molded object when removing the mold. Instead of a sand bed any suitable form of support may be used, but it should be provided with air vents for the purpose above mentioned.

For the purpose of providing means for quickly levelling off the sand beds, 2" x4." timbers are staked or otherwise permanently placed in the ground. These timbers function as tracks and the ground between the same is carefully levelled, sub-graded and packed, a space of one-half inch being left for the final sand bed.

The 2" x 4 timbers or tracks are spaced close enough so that the molds overlap on each' side, thereby bearing directly on the tracks. This prevents sinking down into the sand and, also, prevents production of undersized or deformed blocks, which might be the case if the molds were supported entirely on the sand.

In finishing off the sand bed, preparatory to casting or filling the molds, it is necessary to smoothly finish the sand surface and to leave it slightly raised with relation to the tracks. Unless the sand surface is raised about A; of an inch above the surface of the tracks, feather-edges are formed on the bottom of the blocks,'due to leakage of grout under the partitions of the mold. It is for this reason that care must be taken in smoothing and-finishing off the sand bed. It is, however, easily accomplished by employing av scraper or board such as shownin Fi 4.. This scraper is provided with a pair of inch shims disposed at each end as shown in Fig. 4, and these shims are supported by the tracks. As the scraper is run along the track, thesand surface will be auover the surface of the mold either with a hoe or the float shown in Fig. 5. The molds are placed in row formation, one abutting the other, and the mold man therefore works in one direction, merely seeing to it that enough surplus. concrete is left behind for subsequent settling. As soon as this first rough spreading. is, completed and. there is enough for at least one full mold, the mold "is vibrated by strikin the ends thereof simultaneously with a ew blows evenly distributed from end to end by means of the wooden mallets previously referred to.

The result of this tapping or vibration will be to settle the concrete solidly into the open partitions of the mold, thereby expelling air pockets and producing a more or less wet residue on top of the molds. This surplus is then scraped off and transferred .to the next mold with afew s'trokesof the float or tle hoe, and the mold is then ready to be lifted or stripped with relation to the blocks or poured concrete.

Where three or more molds are used as here illustrated the mold first filled is per mitted to remain until the second, and some- I times the third, mold isfilled, but' as comparatively little time is lost in filling the molds, it can readily be seen that the concrete does not remain long therein and,'under no circumstances, sufficiently long to commence setting. This is important as in lifting the mold vertically away from the poured concrete, the sides of the mold act somewhat as a trowel, thereby forming a series of smooth surfaces both on the interior and exterior of the blocks with very few voids. The blocks, therefore, when set are less impervious to moisture and a desirable finish and texture are 'at the same time obtained. The lifting jack is now employed and it serves two functions, firsti, that'of raising the mold with relation to the oured concrete and, secondly, that of trans erring the mold to an advanced position.

When using the jack it is first necessary to place it in line with the center of the mold to be lifted and to engage it with the angle-iron flanges formed on the ends of the mold. The mold man then bears down on the lever indicated at 20 until the mold is just on the point of lifting; The other helper at this time taps the ends of the mold by means of the mallet and this vibration is sufficient to break the suction between the concrete and the mold. More force is applied to the lever and the operation of raismg the mold is completed with a steady mo- 1 tion until the mold is entirely disengaged from the fresh concrete. The jack is now moved along the tracks as it supports the mold in an elevated possition and it is in this manner that the mold is advanced to a point where it may again refilled. Th1s operation is repeated and repeated until the. endof the set of tracks is reached. The molds are then transferred to the next set of tracks, and the same operation takes place. 7 7

Proper care of the blocks after they are molded is just as important for quality and strength as the amount of cement used in the mix.

. Like concrete inany other form, blocks of can be. handled and piled. The blocks rest-- ing on the beds should be kept thoroughly sprinkled in dry or windy weather, and fresh blocks in the piles should also be kept as wet as possible, this being accomplishedby sprinking them with a hose or by installing a permanent sprinkling system with nozzles at close enough intervals to cover the whole yard.

An important feature of the resent invention is the use of a propery proportioned mixture of cement, sand and rock, and the proper amount of water to give the greatest strength; a satisfactory mixture being one part cement, two and one-half parts sand or its equivalent, and two and One half parts crushed rock or gravel. These are p aced in the mixer in a dry condition and the water is then added The amount of water, after once being determined,

- should be measured in each batch the same as the other materials; the right amount of water being that which will give the mix a mushy consistency. The mix should not be soupy and, on the other hand, it should not be so stiff that it requires ramming into the partitions of the mold as this would result in a porous or cellular texture when the blocks set and harden.

By employing a mold with fixed vertical side walls and removing the mold as well as its core members by moving the same vertically relatively to the molded article, the lateral support for the vertical walls of the plastic material is withdrawn from all sides evenly and simultaneously and in a direction in line with the force of gravity, and thereby the comparatively wet plastic material Wlll remain intact without lateral support even though the plastic material has not acquired an initial set.

The amount of equipment .required b a plant of this character is fairly small. lifting jack, three or four molds, one concrete mixer, and one wheel cart, together with a couple of mallets, a hoe and a float,

' are practically all the equipment required.

Where a plant is laid out as illustrated in Fig. 2, it is possible for four, men to make as many as four thousand blocks per'day of eight hours, or at the rate of three thousand blocks er eight hour da made and stacked.

Ample space is provi ed for thecement, sand and gravel, and ample space is also provided for stacking from thirty to forty thousand blocks. The area shown provides .for six thousand six inch blocks when the beds are completely filled, and with continuous opneration it takes approximately fortyeight ours for the blocks to set and harden. A large output is in this manner obtained;

the cost of manufacture is reduced to a minimum, and great stren h and density are produced as far as qua ity is concerned.

'This application is related to m earlier application Ser. No. 517,009, filed ov. 22, 1921, wherein is shown a multiple mold structure with connected core members suitable for use in practicin the present method. Having thus describe my invention, what I claimand desire to secure byLetters' Pat cut is' l a 1. A method of forming hollow building blocks from cementitious material whic consists of placing upon a supporting sur- I face a mold formed with fixe vertical side walls and having a core memberfixed with relation to said side walls, the mold being open at its top and bottom, filling the space between the side walls and core member with plastic material, causing the plastic material to settle in the mold and thereafter remov-,

ing the mold and core member from the molded article by simultaneously lifting the mold and its related core member vertically from the supporting surface so that the lateral support for the inner and outer walls of the blockis simultaneously and uniformly withdrawn.

2. A method of plastic material whichconsists of placing upon a supporting surface a mold formed with fixed vertical side walls open at its top and bottom, filling the space between the side walls with plastic material of a mushy consistency and thereafter and while the material is still mushy removing the mold by causing relative vertical movement between themold and molded article, whereby the lateral support for the plastic material is withdrawn from all sides evenly and s1- multaneously and in a direction in line with its top and bottom, filling. the space between the side walls with plastic material of a molding objects .from

mushy consistency and thereafter and while the material is still mushy removing the mold by causing relative vertical movement between the mold and molded article, whereby thelateral support for the plastic material is 'withdrawn from all sides evenly and simultaneously andin a direction in line with the forces of gravity.-

4. A method of manufacturing concrete blocks, which consists in placin upon a suitable supporting surface a mo (1 havlng relatively fixed vertical slde walls and open at its to and bottom, pouring concrete into the mol inthe form of a wet mix, tappin the mold to permit the concrete to settle so idly therein, and then removing the mold by lifting it vertically away from the support of the mold movin and the poured concrete beforethe concrete able supporting surface a mold havingrelatively fixed vertical 'side walls and open at its top and bottom, filling said mold with a wet mixture of concrete and lifting the mold vertically away from the concrete before the latter has taken an initial set, whereby the sides of the mold movingover the surfaces of the wet concrete and in contact therewith will impart a troweling effect.

6. A'method of manufacturing hollow concrete blocks, which consists in placing upon a suitable supporting surface a mold having relatively fixed vertical side walls and open at its top and bottom and provided with cores alsohaving vertical side walls,

pouring a wet mixture of concrete into the mold in the spaces formed between the sides of the mold and the core members, and then removing the mold and the core members simultaneously by lifting them vertically away from the support and the poured concrete before the concrete has taken an initial set, whereby the sides of the mold and the core members moving over. the inner and outer surfaces of the wet concrete and in contact therewith will effect.

7. An. apparatus for castin concrete blocks comprising a pair of para el tracks, a supportv formed between the tracks, an open-ended mold adapted to be supported between the tracks and extending crosswise thereof, the lower surface of the mold contacting with the support and the support forming a bottom therefor, means for delivering concrete to the mold, and a lifting jack impart a troweling movable on the tracks and straddling the same and engageable with the mold to raise the mold vertically away from the concrete and the sup ort, and said jack adapted to be moved ong the track to transfer the mold to an advanced position.

8.,A1r apparatus for casting concrete blocks comprising a pair of parallel tracks, a support formed between the tracks, an open-ended mold adapted to be supported between the tracks, the lower face of the mold contacting with the support and said support forming a bottom for the mold,

umen means for delivering concrete to the mold, means for lifting the mold vertically to remove it with relation to the cured concrete and the sup ort, and means or ermitting a longitudina movement to .trans er-the mol to an advanced position.

9. An. apparatus for casting concrete blocks comprising a pair of parallel tracks, a support formed between the tracks, an Open-ended mold adapted to be supported between the tracks, the lower face of the mold contacting with the support and said support forming a bottom for the mold,

means for delivering concrete to the mold, means for lifting the mold vertical to remove it with relation to the poured concrete and the support, means for permitting a longitudinal movement to transfer the mold to an advanced position, and means for preventing the formation ofa vacuum between the bottom of the mold and the support when the mold is to be raised;

I 10. A method of molding objects from plastic materials which consists of placing upon a" supporting surface a mold formed with fixed vertical side walls and open at its top and bottom, filling the space between the side walls with mushy consistency, vibrating the mold to cause the plastic material to settle therein, and thereafter and while the material is still mushy, removing the mold by causing relative vertical movement between the mold and molded article whereby the lateral support for the plastic material is withdrawn from all sides evenly and simultaneously and in a lastic material of a direction in line with the forces of gravity.

11. A method of molding objects from plastic materials which consists of placing upon a vented supporting surface a mold forme with fixed vertical side walls and having a core member supported and carried by said side walls, the mold being open at its top and bottom, filling the space between the side walls and core member with plastic material of a mushy consistency, causing the material to settle Within the mold and thereafter and while the material is still mushy, removing the mold by lifting the said mold and its connected core member vertically from the supporting surface, -whereby the lateral support forallvertical surfaces of the plastic material is withdrawn simultaneousl andevenly and in a direction in line with t e forces of gravity.

WOLCOTT P. STANTQN. 

